An Inexpensive Sound Deadening Alternative to Dynamat

Nothing ruins a sweet sounding ride more than a trunk that vibrates and doors that rattle. While most cars came with some sort of sound deadening from the factory, the older the car, the lower the quality of materials used for sound deadening, and with the heavy resurgence of classic and muscle cars, this becomes a sizable problem.

To solve this problem, companies such as Dynamat offer sound deadening materials and products to fit practically every application. The problem is that these products are very expensive.

What Is and Where to Place Sound Deadening Material?

Sound deadening material is often mistakenly thought of as a shield from outside noises. It should more accurately be thought of as a sound absorber, affixing itself the surface to reduce the surface’s ability to vibrate. Imagine an empty can sitting on a table. Now imagine flicking it with your finger and the tonnnng it makes afterward.

Now imagine holding that can firmly in your hand and giving it the same flick. Where before it resonated and rang, now it merely gives out a short tink. This same principle is applied to sound deadening your vehicle.

The sheet of carbon steel that forms the outermost body of your door acts exactly the same as an empty can. Thick tar, supported by aluminum, which together make up the sound deadening material, act the same way your hand does around that empty can.

Instead of trying to cover up all the spaces in an attempt to block out the noise, try to find spaces in your door’s body and frame where you can turn tonnnngs into tinks. Literally, if you tap a piece of metal and you hear a low pitch ringing, apply material to or around it.

Most luxury vehicles already offer a light dressing of rubber on the door body to absorb road noise, but this too degrades over time, hardening with the hot and cold cycles until it has completely set.

If your vehicle is over five years old, it has seen thousands of hot and cold cycles, so it’s probably safe to assume your factory sound absorber has cured and is therefore less effective if not altogether useless.

Before purchasing sound deadening, you need to break it down and choose which areas you are going to deaden and what properties each section requires.

Doors: wind noise, mechanical rattles and audio vibrations

Floor: road noise, drive-train, and thermal reduction

Firewall: Thermal reduction, road noise, and engine noise

Trunk: Road noise, mechanical rattles, and audio vibrations

Rear Deck: Audio vibrations and mechanical rattles

Roof: Wind noise and thermal reduction

Dynamat Too Expensive? An Alternative

Peel & Seal is an inexpensive alternative to Dynamat and is available at most home improvement centers such as Lowe’s and Home Depot. While this product is packaged for window and door flashing, it is essentially the same as the original Dynamat product, but a lot cheaper.

Peel & Seal is 0.045 inches thick with an adhesive rubberized asphalt sticky back, two layers of high strength polymer film over a reflective aluminum surface.

When we first tried this product, we were skeptical about it’s adhesive properties. We found quickly that this concern was unfounded.

As is always a good practice, clean the area to be sealed. We used a vacuum, compressed air, and finally a damp cloth to clean debris and dusty residue. With a clean surface, this product will adhere quickly and firmly. Ensure you’ve pre-cut and fitted pieces before removing the protective backing.

Use a wall paper seam-roller to smooth out the Peel & Seal — you’ll find that it takes the shape of where you put it.

This product was intended to be used for flashing and as a roof patch — any small holes you may have will be sealed over, and will keep water out.

Consider an extra layer on areas that not only need sound deadening, but thermal insulation as well, such as the firewall.

Our Results

We have used this product on our own vehicles. The oldest project was done roughly 5 1/2 years ago. The Peel & Seal has held up amazingly. In most areas, the product is still completely adhered and has not peeled away in any areas. The doubled up areas that were applied to the firewall and floor above the exhaust also held up very well with no peeling edges or other compromises.

From the Manufacturer of Peel & Seal

Peel & Seal is a unique self-adhesive instant waterproof repair and flashing material. A super reinforced aluminum surface and rubberized asphalt adhesive that will instantly repair gutters and flashings, metal and flat roofs, RVs and mobile homes, trucks and trailers, skylights and anywhere leaks are a problem. Just remove release paper, and press in place for an instant permanent repair.

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